Diffusion Tensor Imaging (DTI) is a special form of magnetic resonance imaging (MRI) that uses computer-based imaging analysis enabling it to display the mapping of the diffusion process of molecules, mainly water, in biological tissues, specifically white matter tracts.
CT scan of brain
Because DTI incorporates tractography methods it can display 3D modeling presentations. Therefore, DTI results can be reconstructed and presented in two- and three-dimensional images. What makes DTI so useful to the medical community, and perhaps an attorney involved in a personal injury suit, is the fact that the color images produced by DTI imaging analysis display nerve fiber tracts in a very dramatic, precise, and vivid manner.
DTI Shows Detail and Makes Diagnosis Much Easier
Structural MRI scans acquired on a 3T magnet
Example of a DTI showing the progression of a traumatic brain injury
How Does DTI Work?
Because DTI is a more sophisticated type of MRI imaging, it can visually track nerve fibers, which in turn allow a medical professional to easily identify disruptions that may have been caused by an injury. Additionally, DTI allows one to estimate the amount of damage to nerve fibers that are connected to the white matter of the brain. DTI works by measuring the restricted diffusion of water as it traverses and travels through brain tissue and is also used to track a nerve fiber or path through which information travels in the brain. Explaining how DTI works requires the realization that water does not freely diffuse in every direction within the brain because surrounding tissues limit the movement of water, and, as a result, create preferred directions of water diffusion. Given that fact, one can visualize how it becomes much easier for water to diffuse along the length of a white matter nerve fiber, rather than across it, as it is the path of least resistance. Provided that the manner in which nerve fibers are oriented determines how the water flows, bundles of nerve cells that run parallel to one another make the diffusion of water molecules much easier along the main direction. Thus, DTI captures images and measures the entire process of diffusion, illustrating the path of neural information from the brain, down the spinal cord, and to the peripheral nerves.